• Method 1 : Using the following script to install on linux

echo 'deb https://assets.checkra.in/debian /' | sudo tee /etc/apt/sources.list.d/checkra1n.list
sudo apt-key adv --fetch-keys https://assets.checkra.in/debian/archive.key
sudo apt-get update
sudo apt-get install checkra1n

• Method 2 : Download and install

download from: All Releases
run checkra1n

chmod 755 checkra1n
sudo ./checkra1n -c

mount -o rw,union,update /
echo "" >> /.mount_rw
mv /Applications/Setup.app /Applications/Setup.app.crae
uicache --all
killall backboardd